Adhesion between CVD diamond and WC-Co induced by high-pressure and high-temperature

An innovative route to promote adhesion between CVD diamond and WC-Co substrate, based on a high-pressure and high-temperature processing, is presented. It was investigated the brazing of the film on the substrate using a AgCu–Ti (5 wt.%) filler and the possibility of promoting adhesion without filler at the interface. The advantages of using high-pressure are related to the diamond stability, the minimization of voids at the interface and the enhancement of the diffusion along the interface. The adhesion was evaluated through an adapted shear strength test. The best results for brazing with a AgCu(Ti) filler were obtained in the pressure range between 2.5 and 5 GPa, for temperatures from 900 to 1000 °C. Also, excellent results were obtained without the brazing filler for the pressure range between 2.5 and 7.7 GPa and temperatures higher than 1200 °C.